1. Field of the Invention
The present invention relates to an aspirating device for removing undesirable secretions from a mammalian body and more particularly concerns as aspirating device for use in suctioning undesirable secretions from the trachea of a patient.
2. Description of Related Information
Various forms of respiratory therapy require the use of a ventilator which is a device which provides for the movement of gases into and out of the pulmonary system. Usually a ventilator is used in conjunction with some form of artificial airway or tube which is inserted into the patient's trachea through the mouth (endotracheal tube) or into the patient's trachea through an incision in the patient's neck (tracheostomy tube). The tracheostomy procedure is sometimes preferred because it bypasses and therefore avoids complication with portions of the upper airway.
Artificial airways are established for adequately supporting ventilation for an extended period of time. The artificial airway also prevents a potential danger to the patient by diminishing the patient's ability to cough and to voluntarily remove undesirable secretions from the trachea. Accordingly, the removal of the secretions from a patient having a temporary artificial airway, for example, during therapy involving a ventilator, is affected by aspiration or suctioning. Patients with a substantial amount of secretions require frequent aspiration or suctioning to remove secretions from the trachea.
A known and available suctioning device is a suction catheter as described in U.S. Pat. No. 3,319,628 to Halligan. The suction catheter, as taught by Halligan, is connected to a source of vacuum and is inserted through the artificial airway and into the trachea of the patient wherein the suction forces draw secretions into the catheter and out of the trachea and the artificial airway. Halligan teaches an improved catheter having means for manual regulation of the vacuum forces. In particular, Halligan teaches a suction catheter comprising a flexible catheter having an opening at its distal end and a rigid regulator at its proximal end. The regulator includes a bore which is aligned with the lumen of the catheter and a second bore which is perpendicular to the fluid path of the catheter in the first bore. A finger engaging piece is associated with the regulator and includes a concave surface adapted to recevie the finger of the user for occluding the secondary bore. The secondary bore acts as a bleed so that when it is not occluded, outside air enters the bore in the vacuum line and reduces the vacuum forces at the distal tip of the catheter to substantially zero while occluding the secondary bore with the finger terminates all bleed air and maximizes the vacuum forces at the tip of the catheter and partial occlusion will tend to provide vacuum forces between the two extremes. The catheter taught by Halligan provides an effective device for suctioning the trachea and other body passageways. These suction catheters are simple in structure, maneuverable, easy to regulate with respect to suction forces and disposable. The disposability is believed to be a desirable feature because bacteria encountered in the patient's trachea is deposited on the exterior of the catheter and under certain circumstances will continue to grow and multiply. Also, after removal of the catheter from the patient, other airborne bacteria may contact and grow on the catheter surface. Accordingly, reusing such an instrument is believed to be hazardous to the patient because it could introduce bacteria into the respiratory system and/or expose the user (doctor, respiratory therapist, nurse) to bacteria from the patient's trachea. A similarly structured suction and oxygenation catheter is taught by Gandi et al. in U.S. Pat. No. 4,300,550.
Bradford, in U.S. Pat. No. 3,991,762 teaches a resuable aspirating device for use with the patient ventilation apparatus. In one embodiment, Bradford teaches an aspirating device consisting of a catheter tube and a protective housing. The protective housing includes a patient coupling element slidably positioned so as to surround the catheter tube nearest the end thereof suitable for insertion into the trachea and a vacuum coupling element mounted adjacent to the end of the catheter remote from the end adapted to be inserted into the trachea and a protective envelope exending between the patient coupling element and the vacuum coupling element, formed of a flexible plastic material which distorts and compresses when the vacuum coupling element and the patient coupling element are moved relatively toward one another. The patient coupling element also includes a seal surrounding the catheter tube and adapted to help prevent fluid secretions located on the exterior surface of the catheter from being withdrawn, and an irrigation port suitable for connection to an irrigation source and in communication with the external surface of the catheter tube. Bradford teaches that the aspiration device should remain connected to the ventilation apparatus via the patient coupling element and that the same catheter can be reused many times by a single patient. Although the Bradford aspirating device appears to be more expensive to manufacture it may be an improvement, with respect to cost, if several aspirating procedures can be performed with the same device which remains continuously connected to the ventilator during the patient therapy. Also, the apparatus taught by Bradford, offers the advantage of being usable without disconnecting the ventilator so that it is not necessary to follow the procedure of pre-oxygenating the patient before using the suction catheter and a subsequent re-oxygenating step after use of the suction catheter. In addition, the respiratory therapist is not under the time pressure to perform the suctioning procedure in a minimal amount of time while the ventilator is disconnected.
Although the device taught by Bradford may provide some advantages over the prior art disposable suction catheters, it still has disadvantages. Most notably, the entire outer surface of the catheter which comes in contact with the secretions in the ventilator and in the patient's trachea is moved outwardly into the environment after each use, being protected only by the flexible cover. Although a seal is provided in the patient coupling element and irrigation may minimize the amount of secretion on the exterior of the catheter, it is believed that bacteria on the catheter surface is free to grow while the catheter is outside of the patient housing. Bradford has a further disadvantage in that any imperfection of destruction of the protective envelope may allow contamination of the environment and the respiratory therapist operating the catheter device. In addition, another disadvantage is that if the protective envelope is damaged or contains an imperfection, there is a possibility of infecting the patient with environmental bacteria which passes through the envelope and contaminates the catheter.
Palmer, in the U.S. Pat. No. 4,569,344 teaches an aspirating/ventilating apparatus similar to the apparatus taught by Bradford.
Catheters and catheter assemblies for use in suctioning of the trachea and other passages in a patient's body, for use alone or with a ventilator, both disposable and reusable, have been addressed by the prior art, as alluded to above. However, there is still a need for a simple, straight-forward, reliable, easily fabricated resuable aspirating device having reduced potential for contamination between suctioning procedures.